Please have a try to config the Virtual directory site/test1
on the Azure portal as following screenshot
When we push the WebApp to the Azure, we need to include the virtual directory path in the Site Name and Destination URL sections on the Connection tab
After that we can visit the WebApp with sitename/site1
We also can check the uploaded file from Azure Kudu tool (https://sitename.scm.azurewebsites.net/DebugConsole/?shell=powershell)